diff options
| author | Tejun Heo | 2017-02-08 14:30:56 -0800 |
|---|---|---|
| committer | Linus Torvalds | 2017-02-08 15:41:43 -0800 |
| commit | 4d59b6ccf000862beed6fc0765d3209f98a8d8a2 (patch) | |
| tree | 598294e81b74149a78ebed29b3a9ce6c53b1e1e1 /include/linux | |
| parent | 0911d0041c22922228ca52a977d7b0b0159fee4b (diff) | |
cpumask: use nr_cpumask_bits for parsing functions
Commit 513e3d2d11c9 ("cpumask: always use nr_cpu_ids in formatting and
parsing functions") converted both cpumask printing and parsing
functions to use nr_cpu_ids instead of nr_cpumask_bits. While this was
okay for the printing functions as it just picked one of the two output
formats that we were alternating between depending on a kernel config,
doing the same for parsing wasn't okay.
nr_cpumask_bits can be either nr_cpu_ids or NR_CPUS. We can always use
nr_cpu_ids but that is a variable while NR_CPUS is a constant, so it can
be more efficient to use NR_CPUS when we can get away with it.
Converting the printing functions to nr_cpu_ids makes sense because it
affects how the masks get presented to userspace and doesn't break
anything; however, using nr_cpu_ids for parsing functions can
incorrectly leave the higher bits uninitialized while reading in these
masks from userland. As all testing and comparison functions use
nr_cpumask_bits which can be larger than nr_cpu_ids, the parsed cpumasks
can erroneously yield false negative results.
This made the taskstats interface incorrectly return -EINVAL even when
the inputs were correct.
Fix it by restoring the parse functions to use nr_cpumask_bits instead
of nr_cpu_ids.
Link: http://lkml.kernel.org/r/20170206182442.GB31078@htj.duckdns.org
Fixes: 513e3d2d11c9 ("cpumask: always use nr_cpu_ids in formatting and parsing functions")
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Martin Steigerwald <martin.steigerwald@teamix.de>
Debugged-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Cc: <stable@vger.kernel.org> [4.0+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/cpumask.h | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h index c717f5ea88cb..b3d2c1a89ac4 100644 --- a/include/linux/cpumask.h +++ b/include/linux/cpumask.h @@ -560,7 +560,7 @@ static inline void cpumask_copy(struct cpumask *dstp, static inline int cpumask_parse_user(const char __user *buf, int len, struct cpumask *dstp) { - return bitmap_parse_user(buf, len, cpumask_bits(dstp), nr_cpu_ids); + return bitmap_parse_user(buf, len, cpumask_bits(dstp), nr_cpumask_bits); } /** @@ -575,7 +575,7 @@ static inline int cpumask_parselist_user(const char __user *buf, int len, struct cpumask *dstp) { return bitmap_parselist_user(buf, len, cpumask_bits(dstp), - nr_cpu_ids); + nr_cpumask_bits); } /** @@ -590,7 +590,7 @@ static inline int cpumask_parse(const char *buf, struct cpumask *dstp) char *nl = strchr(buf, '\n'); unsigned int len = nl ? (unsigned int)(nl - buf) : strlen(buf); - return bitmap_parse(buf, len, cpumask_bits(dstp), nr_cpu_ids); + return bitmap_parse(buf, len, cpumask_bits(dstp), nr_cpumask_bits); } /** @@ -602,7 +602,7 @@ static inline int cpumask_parse(const char *buf, struct cpumask *dstp) */ static inline int cpulist_parse(const char *buf, struct cpumask *dstp) { - return bitmap_parselist(buf, cpumask_bits(dstp), nr_cpu_ids); + return bitmap_parselist(buf, cpumask_bits(dstp), nr_cpumask_bits); } /** |